Bears general manager Phil Emery has been staring at a lengthy offseason checklist since the 2013 season fell through a trap door in a 33-28 home loss to the Packers in the regular-season finale.

Emery already has taken care of several huge priorities with contract extensions awarded to key starters such as quarterback Jay Cutler, left guard Matt Slauson and center Roberto Garza, moves that will keep the starting unit of last season's record-setting offense fully intact.

Cornerback Tim Jennings and defensive tackle Jeremiah Ratliff have re-signed as well. But the Bears' defense still has gaping holes. Emery has 19 players whose contracts are scheduled to expire Tuesday. And with free agency closing in, a critical period has arrived for roster remodeling.

"I'm not stressed," Emery said at the NFL scouting combine last month. "I'm excited. Very excited. It's a great challenge. And it's the one that we all sign up for — an opportunity to put together a team and be consistently in the hunt to win championships."

Officially, teams won't be able to finalize deals with free agents outside their own clubs until Tuesday afternoon. But already the window shopping is heating up.

With that in mind, here's our look at the Bears' top five positions of need.

Defensive end

In-house spotlight: Chances seem slim that Julius Peppers will remain on the roster much longer. And he certainly won't be kept around without accepting a significant pay reduction to lessen the roughly $18.2 million cap hit he's currently on the books for in 2014.

Cutting Peppers would free $9.8 million in cap space immediately but also saddle the Bears with close to $8.4 million in dead money still counted against it. Before bidding farewell to Peppers, Emery must make certain he has a viable Plan B at the position.

Corey Wootton is headed for free agency as well. And the Bears are doubtful to give any serious thought to re-signing him until he's much further along in his recovery from the hip surgery he had in January. Meanwhile, Wootton will be free to explore opportunities elsewhere.

Open market watch: Greg Hardy and Brian Orakpo, two of the top-tier pass rushers who seemed headed for free agency, won't make it there after the Panthers and Redskins, respectively, opted to apply the franchise tag to each. So that leaves the Bears eyeing a defensive end shelf that still includes the Seahawks' Michael Bennett, the Bengals' Michael Johnson and the Raiders' Lamarr Houston.

Bennett, 28, may be the most intriguing name, setting up a potential reunion with younger brother Martellus here in Chicago.

Bennett's initial wishes seemed centered around remaining with the Seahawks, with whom he was an energizing presence up front for a Super Bowl-winning defense. But according to national reports, their initial offer has Michael heading for the open market to shop around. An ongoing recruiting pitch from Martellus soon may include Emery in the chorus.

With a major need to resuscitate a flat-lining pass rush, spending big at defensive end could become a legitimate temptation for Emery, particularly with a 2014 draft class that seems thin at the position. The Bears can't afford to hit May without at least one starting-caliber end under contract.

Other names to track: Willie Young (Lions), Everson Griffen (Vikings), Robert Ayers (Broncos).

Defensive tackle

In-house spotlight: Henry Melton's status is the most important piece of the Bears' offseason puzzle. He has not been cleared to return from reconstructive left ACL surgery, so the multimillion-dollar question is whether a team is willing to bet on him regaining Pro Bowl form and pay him accordingly.

The Bears have an informational advantage over other teams because Melton has rehabilitated his knee under their watch for the last four months. They know his condition, work habits and potential better than any other suitor. The Bears want to retain Melton, but they understandably want to protect themselves against the risk of his injury hindering future performance.

The scary scenario for the Bears involves a desperate team that's willing to risk paying Melton top dollar. In that case, the Bears would look elsewhere. They already re-signed Jeremiah Ratliff, who can play Melton's three-technique position. Emery in January praised how disruptive the defense was during the first three games of 2013, which, not coincidentally, were the ones in which Melton played before tearing his ACL.

Reserve Nate Collins also is coming off a torn ACL. He will be a factor on the secondary market.

Open market watch: Given how highly Emery values the under tackle as a driving force of the Bears' defense, don't be surprised if the club makes its biggest splash in this pool.